P532: ACUTE MYELOID LEUKEMIA (AML): UNICENTRIC REPORT ON 1029 PATIENTS DIAGNOSED IN TERTIAL REFERAL CENTER
Authors: A. Fricke, K. Nachtkamp, K. Döhner, B. Hildebrandt, B. Betz, M. Rudelius, M. Seidl, C. Zahner, G. Kobbe, A. Kündgen, P. S. Jäger, B.-N. Baermann, U. Germing
Journal: HemaSphere (2022)

Background: Since 2016 patients with AML can be diagnosed according to the WHO classification proposals. The ELN genetic risk classification is a tool for treatment planning. Aims: In order to validate the WHO and the ELN classification, we collected data from 1029 patients diagnosed and / or treated in our institution from 2005 to 2021. Methods: Patients were followed up until December 2021. Diagnoses were based on cytomorphology, histomorphology, flow cytometry, karyotyping, and molecular genetics performed at the University of Düsseldorf and partly at the University of Ulm. Treatment intensity was defined as follows: no treatment at all, best supportive care (BSC) (including low dose Ara-C and Hydroxyurea), Hypomethylating agents (HMA), induction and consolidation, or allogeneic hematopoietic stem cell transplantation (HSCT). Results: Median age at diagnosis was 64 years (ys) (19 – 94). 46% were females. There were 270 patients with recurrent genetic abnormalities (26.5%), 346 with AML-MRC (34%), 121 with tAML (11.9%), 243 with AML-NOS (23.9%), 3 with myeloid sarcoma (0.3%), 4 with blastic plasmacytoid dendritic neoplasm (0.4%), 20 with biphenotypic AML (2%), and in 22 patients the classification was not possible. 17.7% of patients belong to the good risk category of ELN classification, 21.6% to the intermediate risk category and 30% to the adverse risk group. In 30.7%, the classification was not possible due to missing data. 274 patients were treated with HSCT as most intensive therapy (28%), 348 patients with induction and consolidation (35.6%). 209 patients received HMA (21.4%). 127 patients were treated with BSC (13%) and in 20 patients (2%) no therapy was administered. In 51 patients, AML was diagnosed at our laboratory, but treatment took place outside of our department. The median survival time of the entire group was 18 months with 39% of the patients alive by the end of 2021. Median survival was 21 months in females as compared to 16 months in males (p = 0.04). Patients aged over 65 ys had a median survival of 7 months as compared to 134 months in patients aged less than 65 ys (p < 0.0005). There was no difference in overall survival in patients younger than 50 ys of age. Patients with recurrent genetic abnormalities did not reach median survival whereas median survival of patients with AML-MRC, tAML, and NOS was 11, 12, and 14 month (p < 0.0005). The latter three categories did not differ in terms of median survival (p = 0.23). Within the group of AML with recurrent genetic abnormalities, only the patients with t(6;9) and inv(3) reached median survival whereas all other categories had a favorable outcome. Patients of the good risk ELN group did not reach the median survival time whereas median survival of the intermediate and adverse risk groups was 27 and 12 months (p < 0.0005). Patients who underwent HSCT did not reach median survival. Patients treated with induction and consolidation had a median survival time of 123 months compared to 8 months median survival in patients who got HMA (p < 0.0005). In a multivariate analysis including intensity of therapy, age at diagnosis, and ELN group, only intensity of treatment and ELN group were independently influencing overall survival. Summary/Conclusion: The WHO and the ELN classification could be assessed correctly in about 70% of patients only, primarily due to the missing examination of somatic mutations. The ELN classification together with the treatment intensity have major impact on outcome. Patients who neither receive induction and consolidation nor HSCT are facing an unfavorable outcome, even if they are treated with HMA.